1). Field of the Invention
This invention relates to a panoramic imaging arrangement of the kind capable of capturing, focusing, correcting aberrations and otherwise manipulating light received from a 360.degree. surrounding panoramic scene.
2). Discussion of Related Art
Panoramic imaging arrangements have become popular in recent years for purposes of viewing 360.degree. surrounding panoramic scenes. Older generations of panoramic imaging arrangements generally consisted of revolving periscope-like constructions having relatively complex mechanisms for revolving them. More recently, stationary panoramic imaging arrangements have been developed. A stationary panoramic imaging arrangement generally has one or more lenses, each having a vertical axis of revolution, which are used to refract or reflect light received from a 360.degree. surrounding panoramic scene. The lenses alter the direction of the light, whereafter the light passes through a series of lenses which are located vertically one above the other and which further manipulate the light by, for example, focusing the light or altering the intensity of the light.
The task of receiving light in a sideways direction and altering the direction of the light so that the light then proceeds in a vertical direction is a difficult one. Altering the direction of light to such a degree, especially when coming from a 360.degree. surrounding scene, oftentimes leads to aberrations in the resulting light. These aberrations may include astigmatism of the light, defects in color of the light, a loss of image plane flatness, and other defects, some of which are discussed in more detail herein below.
Relatively complex lenses and lens arrangements have been developed in order to overcome these aberrations and produce an acceptable image. These lens arrangements usually include a large number of lenses and oftentimes have lenses with surfaces which are aspherical (see for example U.S. Pat. No. 5,473,474 issued to Powell). Aspherical lenses are difficult to manufacture and therefore less practical to manufacture than for example spherical lenses.